The field of art to which this invention pertains is the production of a distillable hydrocarbonaceous product from a hydrocarbonaceous feed stream containing a non-distillable component while minimizing thermal degradation of the hydrocarbonaceous feed stream. More specifically, the invention relates to a process for treating a hydrocarbonaceous feed stream containing a non-distillable component to produce a distillable hydrocarbonaceous product and a heavy product comprising the non-distillable component while minimizing thermal degradation of the hydrocarbonaceous feed stream which process comprises the steps of: (a) contacting the hydrocarbonaceous feed stream with a hot first hydrogen-rich gaseous stream having a temperature greater than the hydrocarbonaceous feed stream in a flash zone at flash conditions without indirect heat exchange thereby increasing the temperature of the hydrocarbonaceous feed stream and vaporizing at least a portion thereof to provide a hydrocarbonaceous vapor stream comprising hydrogen and a heavy product comprising the non-distillable component; (b) removing the hydrocarbonaceous vapor stream comprising hydrogen from the flash zone without contacting the vapor stream with hydrocarbonaceous liquid; (c) condensing at least a portion of the hydrocarbonaceous vapor stream comprising hydrogen to provide a second hydrogen-rich gaseous stream and a liquid stream comprising distillable hydrocarbonaceous compounds; and (d) recovering a distillable hydrocarbonaceous product from the liquid stream comprising distillable hydrocarbonaceous compounds.